Yahoo! "most abused" web mail service

Stephen Withers
Friday, 07 March 2008 11:05

Business IT - Security

Yahoo! Mail is the source of almost nine out of ten spams coming from web mail services, a security provider has claimed.

According to MessageLabs, Yahoo! Mail was the Yahoo! Mail was the most abused web mail service responsible for sending 88.7 percent of all Web mail-based spam during February.

And as Websense previously reported, spammers have found a way of beating Gmail's CAPTCHA scheme. MessageLabs noted a doubling in the proportion of spam coming from Gmail to 2.6 percent, "mainly promoting adult oriented websites." Yeah, I wondered why those had started showing up in my mailbox again. The Yahoo! Mail CAPTCHA system was broken in July 2007, so we can expect spam from Gmail accounts to ramp up over a similar period.

"There are several approaches a spammer can take to defeat a CAPTCHA," said MessageLabs' chief security analyst, Mark Sunner.

"Whether they do so using an algorithm, a 'mechanical turk' [a human deliberately or unwittingly solving CAPTCHAs for malicious purposes] or combination of the two, email providers are feeling the pressure to keep pace but are limited to what a human can realistically solve creating ever more doubt surrounding the long-term effectiveness of the CAPTCHA as a security mechanism for protecting email services from abuse."

Those numbers sounds bad, but MessageLabs admits that less than five percent of all spam originates from web mail services. 88.7 percent of five percent of many millions is still a lot of messages, but even if that part of the problem was solved overnight we would all still be getting far more spam than we'd like.

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